package com.snailhd.framework.util.base;


public class StringUtil {

    public final static char UNDERLINE = '_';

    /**
     * 转驼峰
     * 默认首字母小写
     */
    public static String camelCase(String str){
        return camelCase(str,false);
    }

    /**
     * 转驼峰
     */
    public static String camelCase(String str,boolean firstUpper){
        return camelCase(str,firstUpper,UNDERLINE);
    }

    /**
     * 转驼峰
     */
    public static String camelCase(String str,boolean firstUpper,char separator){
        if (str==null||"".equals(str.trim())){
            return "";
        }
        int len=str.length();
        StringBuilder sb=new StringBuilder(len);
        for (int i = 0; i < len; i++) {
            char c = Character.toLowerCase(str.charAt(i));
            if (c == separator){
                if (++i<len){
                    sb.append(Character.toUpperCase(str.charAt(i)));
                }
            }else{
                sb.append(c);
            }
        }
        return sb.toString();
    }


    /**
     * Unicode 转中文
     * @param content 内容
     * @return 解码字符串
     */
    public static String decodeUnicode(String content) {
        char aChar;
        int len = content.length();
        StringBuilder outBuffer = new StringBuilder(len);
        for (int x = 0; x < len;) {
            aChar = content.charAt(x++);
            if (aChar == '\\') {
                aChar = content.charAt(x++);
                if (aChar == 'u') {
                    int value = 0;
                    for (int i = 0; i < 4; i++) {
                        aChar = content.charAt(x++);
                        switch (aChar) {
                            case '0':
                            case '1':
                            case '2':
                            case '3':
                            case '4':
                            case '5':
                            case '6':
                            case '7':
                            case '8':
                            case '9':
                                value = (value << 4) + aChar - '0';
                                break;
                            case 'a':
                            case 'b':
                            case 'c':
                            case 'd':
                            case 'e':
                            case 'f':
                                value = (value << 4) + 10 + aChar - 'a';
                                break;
                            case 'A':
                            case 'B':
                            case 'C':
                            case 'D':
                            case 'E':
                            case 'F':
                                value = (value << 4) + 10 + aChar - 'A';
                                break;
                            default:
                                throw new IllegalArgumentException("Malformed   \\uxxxx   encoding.");
                        }

                    }
                    outBuffer.append((char) value);
                } else {
                    if (aChar == 't') {
                        aChar = '\t';
                    }
                    else if (aChar == 'r') {
                        aChar = '\r';
                    }
                    else if (aChar == 'n') {
                        aChar = '\n';
                    }
                    else if (aChar == 'f'){
                        aChar = '\f';
                    }

                    outBuffer.append(aChar);
                }
            } else{
                outBuffer.append(aChar);
            }

        }

        return outBuffer.toString();
    }
}
